WO2021165983A1

WO2021165983A1 - Electrode holder

Info

Publication number: WO2021165983A1
Application number: PCT/IN2020/050920
Authority: WO
Inventors: Sumit Dhody
Original assignee: Sumit Dhody
Priority date: 2020-02-21
Filing date: 2020-10-31
Publication date: 2021-08-26

Abstract

The present disclosure relates to electrode holders having their body and mouth portion made of dissimilar compositions that is capable of providing enhanced service life of up to three times, along with increased ability to withstand intense impacts of welding, and huge stresses involved in repeated heating and cooling cycles of welding process. The superior composition of mouth piece of the electrode holder provides supreme strength to withstand any deformation during usage thereby saving heavy cost of replacement and time.

Description

GOLD COIN ELECTRODE HOLDERS

FIELD OF INVENTION

The present invention is directed to electrode holders, and more particularly to superior composition of electrode holders contributing to its enhanced service life.

BACKGROUND OF INVENTION

In current resistance welding products, the main agenda in the market for a better performance is to provide long life of the front end mechanical system comprising of weld electrodes and electrode holders. These welding electrodes and holders function to force the work pieces together and hold them during the weld. Further, they provide the current path, welding pressure or force, weld current, follow-up force as the work pieces fuse and forge together, finally cooling the work pieces after the weld. Hence, development of these electrodes and electrode holders is a very important aspect.

Since most of the vehicle body welding presently is done by robots, any down time affects the cycle time & hence the throughput of number of vehicular bodies welded. This is a prominent evolving problem across the vehicle industry. Most of down time consists of replacement of electrodes followed by its holders. Since the entire setup is to be checked and aligned prior to welding; it takes lot of time and effort thus affecting throughput of the plant.

These electrode holders are often called shanks, adaptors, holders or gun arms, and are primarily of tube type construction, either straight or bent (likely in most cases) with one end having provision of insertion of cap tips / electrodes while the other end remains fixed to machine. The cooling water circuit consisting of a copper tube is provisioned through the internal space within the holder. The continued problem here is also of frequent failure of holders in welding line, which thereby demands for life improvement of the holders.

Importantly, the problem has been found more prevalent in case of bent holders, where the manufacture of holder generally witness a long lead and setup time while changing the holders, besides being a tedious and time consuming task. Conventionally, these bent arms were made by casting with brass, copper, aluminium etc. However, in modern days it is progressively replaced by integral bent arms made out of drawn tubes of much better materials like chromium copper, chromium zirconium copper, beryllium copper etc.

Until today, the challenge identified was regarding the designing of the cap tip insertion portion of the holder, which had to bear the impact forces while welding. Since lot of heat is generated during welding, and inspite of continued process of cooling down the intense heat by circulating water, the continuous usage causes the partial amount of heat to be transferred through the tip engagement area to the water. Hence it has to bear the stresses created by heating and cooling cycle apart from the impact forces. Furthermore, the sectional area for insertion point is quite thin, which makes it more susceptible for withstanding high impact forces thereby frequently deforming the mouth area of the holder.

In the background of foregoing limitations, there exists a need for sturdy and rigid electrodes and electrode holders for welding line that have strong service life, capable of effectively withstanding high impact forces along with the stresses during welding that obviates the frequent need of changing these holders for various reasons mentioned above.

OBJECT OF THE INVENTION

The primary objective of the present disclosure is to devise strong and sturdy electrode holders that are capable of holding off huge impact forces and stresses and that has maximum thermal conductivity and electrical conductivity possible.

In one other objective of the present disclosure, the robust electrode holders have enhanced service life that obviates repeated replacement of these holders during welding.

Another objective of the present disclosure is to provide an economized electrode holders consisting of material composition of superior strength that gives required rigidity to the end product.

Another objective of this disclosure is to increase work productivity in vehicle body welding process with a supreme composition of electrode holders that prevents quick deformation thereof.

SUMMARY OF THE INVENTION

The present invention is directed to an electrode holder that comprises of a first end composed of beryllium copper material, a body composed of chromium zirconium copper at regions other than the first end. In one significant aspect of present disclosure, the first end is integrally welded with the body to generate the electrode holder with enhanced service life.

These and other aspects, features and advantages of the present invention will be described or become apparent from the following detailed description of preferred embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Before the present process of manufacturing resistance welding products such as electrodes and electrode holders is described, it is to be understood that this disclosure is not limited to the particular method or process or product of given specifications for achieving so, as described, since it may vary within the specification indicated. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present invention, which will be limited only by the appended claims.

The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. The disclosed embodiments are merely exemplary methods of the invention, which may be embodied in various forms.

In a vehicle body welding industry, resistance welding products comprising of weld electrodes and weld electrode holders having prolonged service life is a major requirement. There are various methodologies through which these products are known to be manufactured, however, one of the major challenges that arise for bent holder is regarding the ability of bent arms to bear intense impact forces and associated stress of welding.

To counter the above concern, the first aspect of present disclosure demonstrates a way of strengthening these resistance welding products, thus eliminating the need of frequent replacement of deformed holders, saving lots of time and energy. In accordance with one preferred embodiment, the holder 50 having its first end or conveniently called mouth portion 10 for purposes of present disclosure, is replaced with a material composition that provides maximum strength and robustness to overall product.

In accordance with one exemplary embodiment, and as shown in Fig. 1, the material composition of holder 50 comprises of chromium zirconium copper material including 2% of Beryllium copper material. Now, let’s say, while the first end 10 is made of a composition material of type 1, the remaining part of the holder i.e. part other than the mouth portion or body 20, is made of a different material, say for example, a dissimilar copper material.

The beryllium copper mouthed electrode holder 50 gives the required strength for the mouth area 10 to withstand usual cyclical forces. Further, the given superior composition enables the mouth shape of electrode holder 50 to withstand any deformation during usage. In conventional electrode holders made up of chromium zirconium copper, there is a usual lower hardness in nipple area, besides high tip wear out issue and shortened life span.

Following from above, the newly designed holder 50 having two dissimilar copper materials, needs to be welded. This will now require a superior welding process that can affix these portions in a weld smoothly and firmly. In one example embodiment, such a welding process may be an electron beam welding process which provides a metallurgical joint with very high joint strength.

The electrode holder with a newly designed composition materials, precisely, beryllium copper mouth portion 10 and chromium zirconium copper body portion of remaining portion 20 that are integrally welded using electron beam welding, now has an enhanced service life of the holder 50 that can be guaranteed up to almost three times. In one other exemplary aspect of preset disclosure, a tabular representation of material composition of electrode holder 50 is presented here below:

Item	Material	Hardness	Conductivity	Tensile Strength
Holder body	Chromium Zirconium Copper	70 HRB	85% IACS	450 MPa
Holder Mouth Portion	2% Beryllium Copper	35 HRC	20% IACS	1250 MPa

In one general embodiment, the chromium zirconium copper has an approximate composition as listed: Cr: 0.5-1.5%, Zr: 0.05-0.25% and rest is Cu. This has an approximate hardness ranging between 70-83 HRB. Moreover, 2% Be Cu has a typical composition as: Be: 1.8-2.0%, Co: 0.2%, Si: 0.2%, Al: 0.2% ad rest is Cu. This composition has an approximate hardness between 36-44 HRC.

The resulting holder 50 as discussed above possess a higher life and thus result in increased productivity. The beryllium copper nipple 10 that is electron beam welded to chromium zirconium copper holder body 20 has more hardness, particularly at nipple area. This also adds to high hardness at tip that makes its wear out issues less, while increasing the overall life of the holder 50.

The exemplary product composition described in the embodiments presented previously are illustrative, and, in alternative embodiments, certain acts can be performed in a different order, in parallel with one another, omitted entirely, and/or combined between different exemplary embodiments, and/or certain additional acts can be performed, without departing from the scope and spirit of the invention. Accordingly, such alternative embodiments are included in the inventions described herein.

Claims

An electrode holder (50), comprising:
a first end (10) composed of beryllium copper material;
a body (20) composed of chromium zirconium copper at regions other than the first end,
wherein the first end (10) is integrally welded with the body (20) to generate the electrode holder (50) with enhanced service life.
The electrode holder (50), as claimed in claim 1, wherein the first end (10) is composed of beryllium, cobalt, silicon, aluminum and copper.
The electrode holder (50), as claimed in claim 2, wherein the beryllium concentration ranges between 1.8-2.0%.
The electrode holder (50), as claimed in claim 2, wherein the cobalt concentration is approximately 0.2%.
The electrode holder (50), as claimed in claim 2, wherein the silicon concentration is approximately 0.2%.
The electrode holder (50), as claimed in claim 2, wherein the aluminium concentration is approximately 0.2%.
The electrode holder (50), as claimed in claim 1, wherein the body (20) has chromium concentration ranging between 0.5-1.5%.
The electrode holder (50), as claimed in claim 1, wherein the body (20) has zirconium concentration ranging between 0.05-0.25%.
The electrode holder (50), as claimed in claim 1, wherein the first end (10) has a hardness ranging between 36-44 HRC.
The electrode holder (50), as claimed in claim 1, wherein the body (20) has a hardness ranging between 70-83 HRB.
The electrode holder (50), as claimed in claim 1, wherein the first end (10) is integrally welded with the body using electron beam welding.